This invention relates to a protective cowling for an outboard motor and more particular to an improved protective cowling arrangement for permitting the induction of air for engine operation and precluding the entry of water that could damage the engine and/or its accessories.
As is well known, outboard motors include a power head that contains the powering internal combustion engine and a protective cowling which encircles the engine for its protection from the elements and so as to improve the appearance of the outboard motor. However, the engine requires substantial amounts of airflow for its combustion process. Therefore, it is necessary to provide air openings in the protective cowling through which air may be drawn from the atmosphere for the engine operation. This gives rise to a number of design challenges.
Normally it has been the practice to provide an air inlet at the upper rear portion of the protective cowling which atmospheric air can be drawn for the engine combustion. Such inlet openings are normally formed by a recess that is formed in the main cowling member and which has one or more vertically disposed openings that permit flow of air from this recess to the interior of the cowling. The recess is enclosed by a further cover member that is affixed to the main cover member and which defines either by itself or in combination with the main cover member an atmospheric air opening through which the atmospheric air flows to the cavity which is defined by the main cowling member and the cover member. The air flows through the openings into the interior of the main cowling member.
Normally these openings for the atmospheric air face rearwardly so that water spraying during the operation of the watercraft will not enter them. In addition, normally some form of baffling or labyrinthian type flow arrangement is provided in the inlet device for assisting in separating water from any air that passes into the interior of the protective cowling.
The rearwardly facing air inlet openings, however, can cause a problem in that when the watercraft is suddenly decelerated. Water may splash up and enter the opening. Although the baffling can provide some assistance and assurance against water entry into the interior of the protective cowling, this is an area that can be subject to improvement.
It is, therefore, a principal object of this invention to provide an improved protective cowling for an outboard motor.
It is a further object of this invention to provide an air inlet arrangement for the outboard motor protective cowling that will permit adequate airflow and will ensure against water impingement upon the engine and its accessories.
Obviously it is possible to restrict the size of the openings in the protective cowling that communicate the interior with the air inlet chamber. However, if these openings are restricted, then the performance of the engine can deteriorate, particularly under wide open, full throttle conditions.
It is, therefore, a still further object of this invention to provide an improved protective cowling arrangement that has air openings for adequate air flow but wherein the openings are disposed and arranged so that critical components of the engine can be protected.
Obviously certain portions of the engine are less prone to attack from corrosion and damage from the water than others. For example, the ignition system including the spark plugs, spark coils and spark wires, can be seriously affected if water impinges upon them. Misfiring can occur or in extreme situations the actual running of the engine can be interrupted. In a similar manner, the carburetion and/or throttle arrangement and charge forming system can be subject to deterioration if water impinges upon it. Of course, these problems are particularly aggravated if the engine is operated in the marine environment since the salt water will cause much more corrosion than fresh water.
It is, therefore, a still further object of this invention to provide an improved protective cowling arrangement for an internal combustion engine that permits adequate airflow to the engine for its combustion but wherein the openings are disposed and arranged in such a way as to ensure that water will not impinge upon critical portions of the engine and its accessories which may be adversely affected by water.